Here is my use case: I have a content type called "Maintenance Tasks" which has a maintenance due date (ISO Date) and a number field (have tried integer and decimal) which indicates how often the task should be done (Every X days). I have a few Views that will show tasks that are past due, and I have created a button for someone to click when they have completed the task.

Right now, I can get my rule to change the date by a fixed amount (i.e. now +30 days), but I cannot get it to change by a variable amount, namely "now +[field_frequency] days." Has anyone worked out how to do this? I have searched quite a bit, and I've tried various appraoches with "Calculate a value," but I can't get the system to read my number field and change the date field based on the number field.